Gem stone



FIG. 1 is a top side perspective view of a gem stone showing our new design;

FIG. 2 is a bottom side perspective view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a side view thereof; and,

FIG. 6 is another side view thereof. 

CLAIM The ornamental design for a gem stone, as shown. 